Seismologist rules out earthquake as cause of event near Fort St. John

A screenshot of data recorded by seismographs in Northern B.C. between 10:33 and 10:38 p.m. on October 18th, 2017. Station BMTB is located at Bullhead Mountain near Hudson's Hope. Other seismographs are located in the Fort St. John area. Photo by Dr. Honn Kao/Geological Survey of Canada.

UPDATE: BC Hydro spokesperson Bob Gammer said that Hydro was not involved with the event that occurred on Wednesday night. Gammer explained that the loud ‘bang’ experienced across the Fort St. John area was not caused by a malfunction with any of the Corporation’s equipment. He added that there was no explosion that occurred at either the Site C dam construction, or at the Wuthrich Quarry northwest of Fort St. John. Gammer explained that though crews working on Site C have been conducting blasting at both sites, those activities do not take place during the evening or overnight hours.

FORT ST. JOHN, B.C. — A seismologist with the Geological Survey of Canada said that he is not sure exactly what caused a loud noise and vibration felt by residents of the Peace Region last night, but that an earthquake has been ruled out as the cause.

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A number of residents in Fort St. John, Charlie Lake, Taylor, and as far away as Hudson’s Hope reported on social media hearing a loud noise and associated vibration shortly after 10:30 p.m. Wednesday. According to first-hand accounts from our reporters, the event was described as sounding and feeling like a vehicle impacting a building.

Dr. Honn Kao with the Geological Survey of Canada said that he looked at data from several seismographs in the Fort St. John area, and that he found no evidence of an earthquake that occurred yesterday evening. Dr. Kao explained that after running the data collected from seismographs, he said that was able to find evidence of small vibrations in the seismic waveforms, but that they do not suggest an earthquake.

A screenshot of data recorded by seismographs in Northern B.C. between 10:28 and 10:33 p.m. on October 18th, 2017. Station BMTB is located at Bullhead Mountain near Hudson’s Hope. Other seismographs are located in the Fort St. John area. Photo by Dr. Honn Kao/Geological Survey of Canada.

A screenshot of data recorded by seismographs in Northern B.C. between 10:33 and 10:38 p.m. on October 18th, 2017. Station BMTB is located at Bullhead Mountain near Hudson’s Hope. Other seismographs are located in the Fort St. John area. Photo by Dr. Honn Kao/Geological Survey of Canada.

A screenshot of data recorded by seismographs in Northern B.C. between 10:38 and 10:43 p.m. on October 18th, 2017, with the M4.6 earthquake centred near Anchorage, Alaska clearly marked at several of the stations. Station BMTB is located at Bullhead Mountain near Hudson’s Hope. Other seismographs are located in the Fort St. John area. Photo by Dr. Honn Kao/Geological Survey of Canada.

“The way that you locate earthquakes is you try and find coherent arrivals of seismic waves so that you can pinpoint the source of those waves,” said Dr. Kao. “By looking at all the seismic waveforms at these stations, I cannot see coherent arrivals of seismic phases from a particular source near Fort St. John. We do see at different stations, they all have different noise sources, but its not clear to me that there is a relatively coherent arrival of seismic source that corresponds to any earthquake in that time.”

According to Dr. Kao, though a magnitude 4.6 earthquake was recorded by both Earthquakes Canada and the U.S. Geological Survey and did show up on seismographs in the area, he explained that the intensity of those seismic waves in Northeast B.C. were too small to be detected by humans.

An official with the B.C. Oil and Gas Commission also said this morning that while they did not experience the event first hand, they were aware of it. The OGC’s Director of Public and Corporate Relations Phil Rygg said that the Commission had not received a report of an incident at an oil and gas industry site in the area, but that the Commission was looking into it.

Fort St. John Fire Chief Fred Burrows said that the fire department also received a number of phone calls about the event, but that fire crews were not dispatched to an incident.

Though at least one report on social media suggested that the cause of the noise came from the sky, an official with NORAD at least partially discounted that theory. Canadian Navy Lt. Marco Chouinard with NORAD said that no man-made object, such as a satellite re-entering the atmosphere or a missile, was tracked by defence officials last night. Lt. Chouinard was able however able to say whether the cause of the noise was from a meteor entering the atmosphere, as NORAD does that track those objects.

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